The present invention relates in general to a composite laminate and more specifically to a laminate suitable for use with other laminates such as vinyl.
Vinyl coatings are used for a wide variety of products including furniture, seating covers, upholstery and automotive interiors. Substrates for vinyl coating today are produced from various layers of materials which each have a function. A conventional state of the art construction for the supporting substrate is:
100% polyester needlepunch felt
low density open-celled polyurethane foam
The above structure is then coated with an adhesive. A layer of vinyl polymeric film is then calendered and adhered to the substrate to produce the final laminate product.
The function of each layer is as follows:
Polyester feltxe2x80x94provides the laminate handle, softness, suppleness, and compressibility properties appropriate for use in the manufacture of furniture, luggage, or automotive interiors.
Polyurethane foamxe2x80x94is added to the felt to act as a barrier to keep the adhesive out of the felt to maintain the product soft and supple for the particular application. If the adhesive penetrates the felt, it tends to stiffen the final product and it becomes boardy. The foam has no other function, and does not enhance any of the other properties of the felt sheet. It is an added cost whose function could also be met by the addition of a film laminated to the felt, which is also expensive. The foam also adversely impacts recyclability of the substrate in that the polyurethane is not compatible with polyester when recycling plastics. It is also known that the polyurethane foam, when burned, will decompose to cyanide gas which is a safety issue with this material construction.
In adhering the vinyl coating to the substrate, an adhesive coating, typically a water-based latex, is used. The dimensional stability of this product is an ongoing problem with the laminate manufacturing process.
It can be seen from the above that there is a need for lower cost felt substrates, and furthermore, a substrate which can overcome the problems described above which are associated with current substrates.
It is therefore an object of the present invention to provide a relatively low cost adhesive coated felt.
It is another object of the present invention to provide an adhesive coating for a felt which obviates the need for a barrier layer and reduces production cost.
It is a further object of the present invention to provide an economical adhesive coated felt having improved physical properties.
It is yet another object of the present invention to provide an improved adhesive for a felt which eliminates the need for a separate foam barrier layer.
These and other objects are accomplished in accordance with the present invention whereby an adhesive is applied to and resides on the surface of a felt support to provide superior adhesion to vinyl and overcomes the need to prevent adhesive penetration into the felt layer.
More specifically the present invention allows for the elimination of the polyurethane foam by applying a high viscosity adhesive coating to the surface of the felt. Although the present invention illustrates the use of a polyester felt, it should be understood that any suitable felt may be used. For example, nylon, polypropylene, rayon and polyacrylic felts may also be used. The resulting structure has the following advantages over the existing state of the art:
1. Lower cost product.
2. The coating of adhesive does not penetrate into the body of the felt. It is believed that the adhesive resides mainly on the substrate surface, and at most, penetrates only a few fiber thicknesses into the body of the substrate. This provides for substantially all of the adhesive being available for bonding. This objective can be achieved by combination of application techniques and adhesive viscosities. One suitable method of accomplishing the above objective would be the use of a Stork Foam Adhesive Applicator for applying the appropriate adhesive substrate. Because it acts as an adhesive layer and overcomes the need for a barrier layer for the vinyl, the need for a separate polyurethane foam barrier layer is eliminated. The resulting product is very soft and supple.
3. Because most of the adhesive stays directly on top of the felt surface and is available for adhesion, much less adhesive is required to adhere the vinyl polymeric film to the felt layer. The process of the invention uses between about 0.2 and 0.4 oz/yd2 of adhesive addition versus the industry standard of 1.0 to 5.0 oz/yd2. Any process capable of adding the adhesive to the top of a fabric is acceptable for producing this product. This would include coating processes that apply pastes, powdered foamed adhesive processes, hot melt adhesive processes, and any spray processes that can spray thixotropic materials.